―What do you want to be in the future, John?

― I want to be _____ fashion designer. It is ______ interesting job.

A．a; the

B．an; a

C．a; an

D．an; the

.     是植物蒸腾失水的“门户”，也是气体交换的“窗口”。它们是由一对半月形的      细胞围成的空腔。